JS解决IE6下png图片显示带背景色

页面head中需要添加的代码：

<!--[if lte IE 6]>    <script src="JavaScript/DD_belatedPNG_0.0.8a.js" type="text/javascript"></script>        <script type="text/javascript">            DD_belatedPNG.fix('img,  a');        </script>    <![endif]--> 

背景图没有测试。

下边是js源文件：

/*** DD_belatedPNG: Adds IE6 support: PNG images for CSS background-image and HTML <IMG/>.* Author: Drew Diller* Email: [e-mail]* URL: http://www.dillerdesign.com/experiment/DD_belatedPNG/* Version: 0.0.8a* Licensed under the MIT License: http://dillerdesign.com/experiment/DD_belatedPNG/#license** Example usage:* DD_belatedPNG.fix('.png_bg'); // argument is a CSS selector* DD_belatedPNG.fixPng( someNode ); // argument is an HTMLDomElement**//*PLEASE READ:Absolutely everything in this script is SILLY.  I know this.  IE's rendering of certain pixels doesn't make sense, so neither does this code!*/var DD_belatedPNG = {ns: 'DD_belatedPNG',imgSize: {},delay: 10,nodesFixed: 0,createVmlNameSpace: function () { /* enable VML */if (document.namespaces && !document.namespaces[this.ns]) {document.namespaces.add(this.ns, 'urn:schemas-microsoft-com:vml');}},createVmlStyleSheet: function () { /* style VML, enable behaviors *//*Just in case lots of other developers have addedlots of other stylesheets using document.createStyleSheetand hit the 31-limit mark, let's not use that method!further reading: http://msdn.microsoft.com/en-us/library/ms531194(VS.85).aspx*/var screenStyleSheet, printStyleSheet;screenStyleSheet = document.createElement('style');screenStyleSheet.setAttribute('media', 'screen');document.documentElement.firstChild.insertBefore(screenStyleSheet, document.documentElement.firstChild.firstChild);if (screenStyleSheet.styleSheet) {screenStyleSheet = screenStyleSheet.styleSheet;screenStyleSheet.addRule(this.ns + '\\:*', '{behavior:url(#default#VML)}');screenStyleSheet.addRule(this.ns + '\\:shape', 'position:absolute;');screenStyleSheet.addRule('img.' + this.ns + '_sizeFinder', 'behavior:none; border:none; position:absolute; z-index:-1; top:-10000px; visibility:hidden;'); /* large negative top value for avoiding vertical scrollbars for large images, suggested by James O'Brien, http://www.thanatopsic.org/hendrik/ */this.screenStyleSheet = screenStyleSheet;/* Add a print-media stylesheet, for preventing VML artifacts from showing up in print (including preview). *//* Thanks to R閙i Pr関ost for automating this! */printStyleSheet = document.createElement('style');printStyleSheet.setAttribute('media', 'print');document.documentElement.firstChild.insertBefore(printStyleSheet, document.documentElement.firstChild.firstChild);printStyleSheet = printStyleSheet.styleSheet;printStyleSheet.addRule(this.ns + '\\:*', '{display: none !important;}');printStyleSheet.addRule('img.' + this.ns + '_sizeFinder', '{display: none !important;}');}},readPropertyChange: function () {var el, display, v;el = event.srcElement;if (!el.vmlInitiated) {return;}if (event.propertyName.search('background') != -1 || event.propertyName.search('border') != -1) {DD_belatedPNG.applyVML(el);}if (event.propertyName == 'style.display') {display = (el.currentStyle.display == 'none') ? 'none' : 'block';for (v in el.vml) {if (el.vml.hasOwnProperty(v)) {el.vml[v].shape.style.display = display;}}}if (event.propertyName.search('filter') != -1) {DD_belatedPNG.vmlOpacity(el);}},vmlOpacity: function (el) {if (el.currentStyle.filter.search('lpha') != -1) {var trans = el.currentStyle.filter;trans = parseInt(trans.substring(trans.lastIndexOf('=')+1, trans.lastIndexOf(')')), 10)/100;el.vml.color.shape.style.filter = el.currentStyle.filter; /* complete guesswork */el.vml.image.fill.opacity = trans; /* complete guesswork */}},handlePseudoHover: function (el) {setTimeout(function () { /* wouldn't work as intended without setTimeout */DD_belatedPNG.applyVML(el);}, 1);},/*** This is the method to use in a document.* @param {String} selector - REQUIRED - a CSS selector, such as '#doc .container'**/fix: function (selector) {if (this.screenStyleSheet) {var selectors, i;selectors = selector.split(','); /* multiple selectors supported, no need for multiple calls to this anymore */for (i=0; i<selectors.length; i++) {this.screenStyleSheet.addRule(selectors[i], 'behavior:expression(DD_belatedPNG.fixPng(this))'); /* seems to execute the function without adding it to the stylesheet - interesting... */}}},applyVML: function (el) {el.runtimeStyle.cssText = '';this.vmlFill(el);this.vmlOffsets(el);this.vmlOpacity(el);if (el.isImg) {this.copyImageBorders(el);}},attachHandlers: function (el) {var self, handlers, handler, moreForAs, a, h;self = this;handlers = {resize: 'vmlOffsets', move: 'vmlOffsets'};if (el.nodeName == 'A') {moreForAs = {mouseleave: 'handlePseudoHover', mouseenter: 'handlePseudoHover', focus: 'handlePseudoHover', blur: 'handlePseudoHover'};for (a in moreForAs) {if (moreForAs.hasOwnProperty(a)) {handlers[a] = moreForAs[a];}}}for (h in handlers) {if (handlers.hasOwnProperty(h)) {handler = function () {self[handlers[h]](el);};el.attachEvent('on' + h, handler);}}el.attachEvent('onpropertychange', this.readPropertyChange);},giveLayout: function (el) {el.style.zoom = 1;if (el.currentStyle.position == 'static') {el.style.position = 'relative';}},copyImageBorders: function (el) {var styles, s;styles = {'borderStyle':true, 'borderWidth':true, 'borderColor':true};for (s in styles) {if (styles.hasOwnProperty(s)) {el.vml.color.shape.style[s] = el.currentStyle[s];}}},vmlFill: function (el) {if (!el.currentStyle) {return;} else {var elStyle, noImg, lib, v, img, imgLoaded;elStyle = el.currentStyle;}for (v in el.vml) {if (el.vml.hasOwnProperty(v)) {el.vml[v].shape.style.zIndex = elStyle.zIndex;}}el.runtimeStyle.backgroundColor = '';el.runtimeStyle.backgroundImage = '';noImg = true;if (elStyle.backgroundImage != 'none' || el.isImg) {if (!el.isImg) {el.vmlBg = elStyle.backgroundImage;el.vmlBg = el.vmlBg.substr(5, el.vmlBg.lastIndexOf('")')-5);}else {el.vmlBg = el.src;}lib = this;if (!lib.imgSize[el.vmlBg]) { /* determine size of loaded image */img = document.createElement('img');lib.imgSize[el.vmlBg] = img;img.className = lib.ns + '_sizeFinder';img.runtimeStyle.cssText = 'behavior:none; position:absolute; left:-10000px; top:-10000px; border:none; margin:0; padding:0;'; /* make sure to set behavior to none to prevent accidental matching of the helper elements! */imgLoaded = function () {this.width = this.offsetWidth; /* weird cache-busting requirement! */this.height = this.offsetHeight;lib.vmlOffsets(el);};img.attachEvent('onload', imgLoaded);img.src = el.vmlBg;img.removeAttribute('width');img.removeAttribute('height');document.body.insertBefore(img, document.body.firstChild);}el.vml.image.fill.src = el.vmlBg;noImg = false;}el.vml.image.fill.on = !noImg;el.vml.image.fill.color = 'none';el.vml.color.shape.style.backgroundColor = elStyle.backgroundColor;el.runtimeStyle.backgroundImage = 'none';el.runtimeStyle.backgroundColor = 'transparent';},/* IE can't figure out what do when the offsetLeft and the clientLeft add up to 1, and the VML ends up getting fuzzy... so we have to push/enlarge things by 1 pixel and then clip off the excess */vmlOffsets: function (el) {var thisStyle, size, fudge, makeVisible, bg, bgR, dC, altC, b, c, v;thisStyle = el.currentStyle;size = {'W':el.clientWidth+1, 'H':el.clientHeight+1, 'w':this.imgSize[el.vmlBg].width, 'h':this.imgSize[el.vmlBg].height, 'L':el.offsetLeft, 'T':el.offsetTop, 'bLW':el.clientLeft, 'bTW':el.clientTop};fudge = (size.L + size.bLW == 1) ? 1 : 0;/* vml shape, left, top, width, height, origin */makeVisible = function (vml, l, t, w, h, o) {vml.coordsize = w+','+h;vml.coordorigin = o+','+o;vml.path = 'm0,0l'+w+',0l'+w+','+h+'l0,'+h+' xe';vml.style.width = w + 'px';vml.style.height = h + 'px';vml.style.left = l + 'px';vml.style.top = t + 'px';};makeVisible(el.vml.color.shape, (size.L + (el.isImg ? 0 : size.bLW)), (size.T + (el.isImg ? 0 : size.bTW)), (size.W-1), (size.H-1), 0);makeVisible(el.vml.image.shape, (size.L + size.bLW), (size.T + size.bTW), (size.W), (size.H), 1 );bg = {'X':0, 'Y':0};if (el.isImg) {bg.X = parseInt(thisStyle.paddingLeft, 10) + 1;bg.Y = parseInt(thisStyle.paddingTop, 10) + 1;}else {for (b in bg) {if (bg.hasOwnProperty(b)) {this.figurePercentage(bg, size, b, thisStyle['backgroundPosition'+b]);}}}el.vml.image.fill.position = (bg.X/size.W) + ',' + (bg.Y/size.H);bgR = thisStyle.backgroundRepeat;dC = {'T':1, 'R':size.W+fudge, 'B':size.H, 'L':1+fudge}; /* these are defaults for repeat of any kind */altC = { 'X': {'b1': 'L', 'b2': 'R', 'd': 'W'}, 'Y': {'b1': 'T', 'b2': 'B', 'd': 'H'} };if (bgR != 'repeat' || el.isImg) {c = {'T':(bg.Y), 'R':(bg.X+size.w), 'B':(bg.Y+size.h), 'L':(bg.X)}; /* these are defaults for no-repeat - clips down to the image location */if (bgR.search('repeat-') != -1) { /* now let's revert to dC for repeat-x or repeat-y */v = bgR.split('repeat-')[1].toUpperCase();c[altC[v].b1] = 1;c[altC[v].b2] = size[altC[v].d];}if (c.B > size.H) {c.B = size.H;}el.vml.image.shape.style.clip = 'rect('+c.T+'px '+(c.R+fudge)+'px '+c.B+'px '+(c.L+fudge)+'px)';}else {el.vml.image.shape.style.clip = 'rect('+dC.T+'px '+dC.R+'px '+dC.B+'px '+dC.L+'px)';}},figurePercentage: function (bg, size, axis, position) {var horizontal, fraction;fraction = true;horizontal = (axis == 'X');switch(position) {case 'left':case 'top':bg[axis] = 0;break;case 'center':bg[axis] = 0.5;break;case 'right':case 'bottom':bg[axis] = 1;break;default:if (position.search('%') != -1) {bg[axis] = parseInt(position, 10) / 100;}else {fraction = false;}}bg[axis] = Math.ceil(  fraction ? ( (size[horizontal?'W': 'H'] * bg[axis]) - (size[horizontal?'w': 'h'] * bg[axis]) ) : parseInt(position, 10)  );if (bg[axis] % 2 === 0) {bg[axis]++;}return bg[axis];},fixPng: function (el) {el.style.behavior = 'none';var lib, els, nodeStr, v, e;if (el.nodeName == 'BODY' || el.nodeName == 'TD' || el.nodeName == 'TR') { /* elements not supported yet */return;}el.isImg = false;if (el.nodeName == 'IMG') {if(el.src.toLowerCase().search(/\.png$/) != -1) {el.isImg = true;el.style.visibility = 'hidden';}else {return;}}else if (el.currentStyle.backgroundImage.toLowerCase().search('.png') == -1) {return;}lib = DD_belatedPNG;el.vml = {color: {}, image: {}};els = {shape: {}, fill: {}};for (v in el.vml) {if (el.vml.hasOwnProperty(v)) {for (e in els) {if (els.hasOwnProperty(e)) {nodeStr = lib.ns + ':' + e;el.vml[v][e] = document.createElement(nodeStr);}}el.vml[v].shape.stroked = false;el.vml[v].shape.appendChild(el.vml[v].fill);el.parentNode.insertBefore(el.vml[v].shape, el);}}el.vml.image.shape.fillcolor = 'none'; /* Don't show blank white shapeangle when waiting for image to load. */el.vml.image.fill.type = 'tile'; /* Makes image show up. */el.vml.color.fill.on = false; /* Actually going to apply vml element's style.backgroundColor, so hide the whiteness. */lib.attachHandlers(el);lib.giveLayout(el);lib.giveLayout(el.offsetParent);el.vmlInitiated = true;lib.applyVML(el); /* Render! */}};try {document.execCommand("BackgroundImageCache", false, true); /* TredoSoft Multiple IE doesn't like this, so try{} it */} catch(r) {}DD_belatedPNG.createVmlNameSpace();DD_belatedPNG.createVmlStyleSheet();